Toshiba 37RV530U - No standby LED, no reaction to power button being pressed

[Cyax]

Hi there,

I have a (very old) Toshiba 37RV530U that recently stopped working. The power LED is not lighting up in any way, and the TV doesn't react at all to the power button being pressed. Before it died, it was used for several hours a day for the better part of 10 years. Its death coincided with a day we had a couple very short power outages, although it was plugged into a surge protector along with a gaming PC.

The TV was still working great and has some minor sentimental value, but because it's old and not really worth anything anymore, I was mostly hoping to get some idea of if it is even possible or realistic to get parts for it to attempt a repair.

I did some rudimentary testing with my multimeter, and certain readings are way off, so it seems like it definitely has some issues with the power board. For example, two lines labeled 12V are both reading 36V DC, and the DC output on the bridge rectifier is fluctuating every couple of seconds between 145V and 168V. It also seems to be correctly reading 5V on the standby line, but (obviously) won't turn on. I took a good, hard look at the entire power board with a flashlight and was unable to discern any bad capacitors, or any other damage.

I'm very green when it comes to doing this kind of work. Even if I was able to diagnose and repair the power board, is it possible, or even likely, that the logic board is damaged, too? A quick google search told me that finding decade-old parts could prove to be a wild goose chase.

I suppose I'm mostly looking for confirmation from you smart folks that the time and effort that I would put into saving this thing just isn't worth it when the TV realisitically has no value to anyone but me.

Thanks very much for taking the time to read and respond.

[nomoresonys]

Re: Toshiba 37RV530U - No standby LED, no reaction to power button being pressed

Try unplug tv from outlet, unplug cable from powerboard to mainboard leave unplugged, plug tv back into outlet, see if backlights come on and stay on. Is a quick test that will work if your powerboard has pullup resistors. Sometimes old parts are easier to find and cheaper than newer ones due to low demand.

[budm]

Re: Toshiba 37RV530U - No standby LED, no reaction to power button being pressed

1) We need to see the pictures of the whole backside of the TV showing all the boards.
2) We need good clear straight shot for the whole top and bottom side of the power supply board.
3) We need the Voltage readings of all the power supply connector hat goes to the main board, you MUST put down the pin name and follow by the Voltage reading for each pin.
4) Are you 100% sure that you are getting 36V at the 12V pin? That sounds more like a measurement error. To really have 36V on the 12V line, lots of components would have been damaged by now due to over Voltage.

[Cyax]

Re: Toshiba 37RV530U - No standby LED, no reaction to power button being pressed

Try unplug tv from outlet, unplug cable from powerboard to mainboard leave unplugged, plug tv back into outlet, see if backlights come on and stay on. Is a quick test that will work if your powerboard has pullup resistors. Sometimes old parts are easier to find and cheaper than newer ones due to low demand.

I'll try this tomorrow when I have better light to work by. Thanks for the advice.

1) We need to see the pictures of the whole backside of the TV showing all the boards.
2) We need good clear straight shot for the whole top and bottom side of the power supply board.
3) We need the Voltage readings of all the power supply connector hat goes to the main board, you MUST put down the pin name and follow by the Voltage reading for each pin.
4) Are you 100% sure that you are getting 36V at the 12V pin? That sounds more like a measurement error. To really have 36V on the 12V line, lots of components would have been damaged by now due to over Voltage.

Thanks budm, I appreciate the reply. I figured I'd need to to something like that, but I wasn't sure of the exact things steps I needed to complete. Your instructions are clear. I'll get it done tomorrow.

As for 4), you very well might be correct that I made a measurement error. I was using the metal of the TV as ground when I check, but I had a minute tonight and rechecked those specific measurements. I had my multimeter in DC mode, placed the black lead on a ground pin on the same connector as the 12V pins, andplaced the red lead on each of the pins labeled 12V. They read slightly higher than yesterday, at around 38V each. Let me know if I completely blew it somewhere in here.

Thanks again. I'll get those photos done as soon as I can.

[yokoono]

Re: Toshiba 37RV530U - No standby LED, no reaction to power button being pressed

The instrument battery is unloaded and you have measurement errors.

[budm]

Re: Toshiba 37RV530U - No standby LED, no reaction to power button being pressed

Check your meter's battery.